Process for preparing coated organic particles

Abstract

The present invention is in the field of coated organic particles, in particular comprising small molecules, by using atomic layer deposition. It relates to a process for preparing coated organic particles comprising: (a) bringing organic particles containing a halogen-containing organic compound in motion to each other, wherein the halogen-containing organic compound consists of nonmetals, (b) sequentially contacting the organic particles with triethyl aluminum and a decomposition compound in the gaseous state.

Description

[0001] Process for Preparing Coated Organic Particles

[0002] Description

[0003] The present invention is in the field of coated organic particles, in particular comprising small molecules, by using atomic layer deposition.

[0004] Small molecules, for example pharmaceuticals, agrochemicals, or laundry additives are often formulated in order to achieve effects which the pristine molecules do not have. Examples are protection against certain environments, compatibility in various media or controlled release, i.e. release over an extended period of time. A typical approach to achieve this is to encapsulate the compound such that the contained compound is shielded by the capsule shell and is not or only slowly released, for example by diffusion through the shell. Various techniques are available for encapsulation. Atomic layer deposition is a particularly useful technique, as it allows very precise, uniform and very thin deposition of inorganic or organic-inorganic hybrid materials. This allows for high control of the encapsulation, for example an exact tuning of the release profile, and also high active ingredient loading.

[0005] D. Zhang et al. disclose in Nanoscale, volume 9 (2017), pages 11410-11417 the encapsulation of budesonide and lactose. They use a typical atomic layer deposition procedure as it is used in many other applications. However, such a process works for only a very limited number of compounds. Most compounds are destroyed and / or agglomerated in this way.

[0006] US 201810 221 294 A1 discloses a process for coating particles of pharmaceuticals, such as paracetamol, by ALD using trimethylaluminum. This process involves harsh conditions, hence only very stable compounds like paracetamol can be coated without significant degradation. In addition, the particles tend to agglomerate in this process, so they need to be repeatedly deagglomerated during the process which can hardly be done on an industrially feasible scale.

[0007] JP 2022 1039 938 A discloses core-shell particles comprising organo-metallic complexes with a shell formed by ALD. However, organo-metallic complexes are more robust in comparison to many purely organic compounds.

[0008] It was therefore an object of the present invention to provide a coating process which is applicable to a wide range of compounds including sensitive ones, in particular halogen-containing organic compounds. Such a process was aimed for retaining the to be coated compound, leaving it mostly unchanged and at the same time avoid particle agglomeration. The particle shell shall have a very uniform thickness. The process should be robust so it can easily be scaled to industrial scales and allow interference-free production. In one aspect the invention relates to a process for preparing coated organic particles comprising: a. bringing organic particles containing a halogen-containing organic compound in motion to each other, b. sequentially contacting the organic particles with triethyl aluminum and a decomposition compound in the gaseous state.

[0009] In another aspect the invention relates to a process for preparing coated organic particles comprising: a. bringing organic particles containing a halogen-containing organic compound in motion to each other, wherein the halogen-containing organic compound consists of nonmetals, b. sequentially contacting the organic particles with triethyl aluminum and a decomposition compound in the gaseous state.

[0010] In another aspect the invention relates to organic particles containing: a. a core containing a halogen-containing organic compound, wherein the core is essentially free of aluminum, b. a shell containing aluminum, wherein the shell is essentially free of the halogen-containing organic compound, and c. an interlayer between the core and the shell containing at least 5 atomic % aluminum and at least 5 atomic % of the halogen-containing organic compound, wherein the interlayer has a thickness of less than the thickness of the shell.

[0011] In another aspect the invention relates to organic particles containing: a. a core containing a halogen-containing organic compound, wherein the core is essentially free of aluminum and wherein the halogen-containing organic compound consists of nonmetals, b. a shell containing aluminum, wherein the shell is essentially free of the halogen-containing organic compound, and c. an interlayer between the core and the shell containing at least 5 atomic % aluminum and at least 5 atomic % of the halogen-containing organic compound, wherein the interlayer has a thickness of less than the thickness of the shell.

[0012] In another aspect the invention relates to composition containing the organic particles according to the present invention.

[0013] Preferred embodiments of the present invention can be found in the description and the claims. Combinations of different embodiments fall within the scope of the present invention.

[0014] In the process according to the present invention particles containing a halogen-containing organic compound are coated. These particles may also be referred to as organic particles. Organic in the context of the present invention refers to compounds which contain at least one carbon-hydrogen or at least one carbon-carbon bond, preferably they contain at least one carbon-hydrogen and at least one carbon-carbon bond. Often, organic compounds contain more than 80 at.-% of nonmetals, preferably more than 90 at.-%, such as 95 at.-% or 99 at.-%, in particular completely or essentially completely. It is even more preferable that the nonmetals are C, H, 0, N, S, Se and / or P. A halogen-con- taining compound refers to a compound which contain a halogen, i.e. fluorine, chlorine, bromine, iodine, preferably compounds, in which the halogen is covalently bound, in particular compound containing at least one carbon-halogen bond, such as a C-F bond, a C-CI bond, a C-Br bond or a C-l bond. The halogen-containing compound can contain more than one halogen, for example fluorine and chlorine. In particular, the halogen-containing compound contains at least one C-F bond and at least one C-CI bond.

[0015] The organic compound can be an agrochemical, such as an insecticide, a fungicide, or a herbicide. Insecticides include insecticides from the class of the carbamates, organophosphates, organochlorine insecticides, phenyl pyra- zoles, pyrethroids, neonicotinoids, juvenile hormone analogs, alkyl halides, organotin compounds, benzoylureas, METI acarizides, and insecticides such as chloropicrin, flonicamid, clofentezin, hexythiazox, etoxazole, tetradifon, chlorofenapyr, hydramethylnon, fluacrypyrim, or their derivatives.

[0016] Fungicides include fungicides from the classes of dinitroanilines, allylamines, anilinopyrimidines, antibiotics, aromatic hydrocarbons, benzenesulfonamides, benzimidazoles, benzisothiazoles, benzophenones, benzothiadiazoles, benzotriazines, benzyl carbamates, carbamates, carboxamides, carboxylic acid diamides, chloronitriles cyanoacetamide oximes, cyanoimidazoles, cyclopropanecarboxamides, dicarboximides, dihydrodioxazines, dinitrophenyl crotonates, dithiocarbamates, dithiolanes, ethylphosphonates, ethylaminothiazolecarboxamides, guanidines, hydroxy-(2- aminojpyrimidines, hydroxyanilides, imidazoles, imidazolinones, isobenzofuranones, methoxy acrylates, methoxycarbamates, morpholines, N phenylcarbamates, oxazolidinediones, oximinoacetates, oximinoacetamides, peptidylpyrim- idine nucleosides, phenylacetamides, phenylamides, phenylpyrroles, phenylureas, phosphonates, phosphorothio- lates, phthalamic acids, phthalimides, piperazines, piperidines, propionamides, pyridazinones, pyridines, pyridinylme- thylbenzamides, pyrimidinamines, pyrimidines, pyrimidinonehydrazones, pyrroloquinolinones, quinazolinones, quinolines, quinones, sulfamides, sulfamoyltriazoles, thiazolecarboxamides, thiocarbamates, thiophanates, thiophenecarboxamides, toluamides, triphenyltin compounds, triazines, triazoles.

[0017] Herbicides include herbicides from the classes of the acetamides, amides, aryloxyphenoxypropionates, benzamides, benzofuran, benzoic acids, benzothiadiazinones, bipyridylium, carbamates, chloroacetamides, chlorocarboxylic acids, cyclohexanediones, dinitroanilines, dinitrophenol, diphenyl ether, glycines, imidazolinones, isoxazoles, isoxazoli- dinones, nitriles, N-phenylphthalimides, oxadiazoles, oxazolidinediones, oxyacetamides, phenoxycarboxylic acids, phenylcarbamates, phenylpyrazoles, phenylpyrazolines, phenylpyridazines, phosphinic acids, phosphoroamidates, phosphorodithioates, phthalamates, pyrazoles, pyridazinones, pyridines, pyridinecarboxylic acids, pyridinecarboxamides, pyrimidinediones, pyrimidinyl(thio)benzoates, quinolinecarboxylic acids, semicarbazones, sulfonylaminocar- bonyltriazolinones, sulfonylureas, tetrazolinones, thiadiazoles, thiocarbamates, triazines, triazinones, triazoles, triazolinones, triazolocarboxamides, triazolopyrimidines, triketones, uracils, ureas. Mixtures of different pesticides are also suitable.

[0018] The organic compound can be a pharmaceutical. Examples for pharmaceuticals include fluoxetine, albuterol, fluconazole, ciprofloxacin, chloroquine, chlorpromazine, iodixanol, bromocriptine, fludrocortisone.

[0019] The organic compound can be cleaning additives, such as surfactants, antimicrobial agents or chelating agents. Examples are triclosan, perfluorinated compounds (PFCs) like perfluorooctanoic acid (PFOA), trichloroisocyanuric acid (TCCA), dichloroisocyanurate (DCCNa), sodium dichloroisocyanurate (NaDCC),

[0020] The organic compound preferably contains a functional group, in particular a hydroxyl group, an aldehyde or ketone group, an ether group, an ester group, an amid group, an amine group, an imine group, a nitrile group, a thiol group, a thioether group, a thioketone group, a sulfoxide group, a sulfone group, or an olefin group. The organic compound preferably has a molecular weight of less than 2000 g / mol, more preferably less than 1000 g / mol, in particular less than 600 g / mol.

[0021] Preferably, the organic particles have a weight-mean average particle size of 0.5 to 1000 m, more preferably 1 to 200 pm, even more preferably 1.5 to 100 pm, in particular 2 to 50 pm, for example 2 to 8 pm or 5 to 20 pm. Average particle size is preferably measured by light scattering.

[0022] In step (a) of the process according to the present invention, the organic particles are brought in motion to each other. This can be achieved in various ways, for example by using mixers such as plough share mixer, free fall mixer, or blender; dryers such as paddle dryer; acoustic mixers; fluidized bed reactors; spouted bed reactors or rotating drums; spatial reactors such as conveying reactors; vibratory or pulsed-vibratory equipment; or cascades such as a cascade of mixers, dryers or spatial reactors. Combinations of different techniques are also suitable, such as fluidization in combination with vibration. Fluidized bed reactors are preferred, in particular fluidized bed reactors in combination with vibration. Hence, preferably, the organic particles are fluidized.

[0023] Bringing the organic particles in motion to each other typically avoids agglomeration of the organic particles during the coating process and yields organic particles with more homogeneous coatings. Step (a) may be operated such that it constitutes a drying step. This can be done by purging the organic particles with dry air or an inert gas such as nitrogen or argon, for example for 10 min to 2 h, at room temperature or elevated temperature, for example 30 to 80 °C.

[0024] Preferably, the organic particles are brought in contact with a pretreatment compound in the gaseous state before step (b), i.e. before the organic particles are brought in contact with the metal- or semimetal-containing compound. The pretreatment compound is preferably water, an alcohol or a carboxylic acid. Alcohols include mono alcohols like methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, iso-butanol, tert-butanol; and diols like ethylenediol, propylene-1 ,2-diol, butane-1,2-diol, butane-1,4-diol, hexane-1 ,2-diol, hexane-1 ,4-diol. Carboxylic acids include monocarboxylic acids like formic acid, acetic acid, propionic acid, butyric acid, lactic acid, pyruvic acid, glycine, alanine; and dicarboxylic acids like oxalic acid, malonic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, citric acid, tartronic acid, mesoxalic acid, tartaric acid, malic acid. Preferably, the pretreatment compound has molecular weight of 500 g / mol or less, in particular 200 g / mol or less. Preferably, the pretreatment compound has a vapor pressure of at least 1 mbar at 80 °C. Preferably, the organic particles are brought in contact with a pretreatment compound in the gaseous state while the organic particles are kept in motion.

[0025] Preferably, the organic particles are brought in contact with the pretreatment compound for 1 s to 30 min, in particular 1 min to 10 min. Preferably, the organic particles are brought in contact with the pretreatment compound at a temperature of 0 °C to 150 °C, more preferably 20 °C to 120 °C, in particular 25 °C to 80 °C. Preferably, the organic particles are brought in contact with the pretreatment compound at a partial pressure of the pretreatment compound of 1 mbar to 1 bar, more preferably 2 to 100 mbar, in particular 5 to 100 mbar. Preferably, the organic particles are brought in contact with a mixture of the pretreatment compound in the gaseous state and an inert gas, for example nitrogen or argon. The mixture of the pretreatment compound in the gaseous state and an inert gas may have a pressure around ambient pressure, such as 0.8 to 1 .2 bar. The pretreatment compound can be brought into the gaseous state by techniques described for the metal- or semimetal-containing compound described below. Preferably, any excess pretreatment compound is removed from the gaseous state after the organic particles have been brought in contact with the pretreatment compound and before the organic particles are brought in contact with the metal- or semimetal-containing compound. Such removal can be effected by evacuation or purging, for example with an inert gas such as nitrogen or argon. Evacuation or purging can take 10 s to 1 h, preferably 1 to 45 min, in particular 5 to 30 min.

[0026] According to the present invention, in step (b) the organic particles are sequentially contacted with triethyl aluminum (TEA) and a decomposition compound in the gaseous state. Sequentially may mean that the organic particles are firstly brought in contact with TEA and subsequently with a decomposition compound. Hence, a sequence is performed which contains contacting the organic particles with TEA and contacting the organic particles with a decomposition compound. This sequence can be performed 1 to 500 times, preferably 2 to 100 times, for example 3 to 20 times or 10 to 50 times. Preferably, the organic particles are contacted with the metal- or semimetal-containing compound for 10 s to 1 h, preferably 1 to 45 min, in particular 5 to 30 min.

[0027] Preferably, residual TEA in the gaseous state is removed before the organic particles are brought in contact to the decomposition compound. Preferably, residual decomposition compound in the gaseous state is removed before the organic particles are brought in contact to TEA. Removal can be achieved by evacuation or by purging with an inert gas, for example nitrogen or argon. Hence, the sequence may contain contacting the organic particles with TEA compound, removing residual TEA from the gas phase, contacting the organic particles with a decomposition compound and removing residual decomposition compound from the gas phase. Evacuation or purging can take 10 s to 1 h, preferably 1 to 45 min, in particular 5 to 30 min.

[0028] Preferably, the decomposition compound is capable of reacting with TEA and thereby forming functional groups which can react with further TEA. Various decomposition compounds are suitable including a plasma like an oxygen plasma, hydrogen plasma, ammonia plasma, nitrous oxide or nitrogen plasma; oxidants like oxygen, oxygen radicals, ozone, nitrous oxide (N2O), nitric oxide (NO), nitrogendioxde (NO2) or hydrogenperoxide; ammonia or ammonia derivatives for example tert-butylamine, iso-propylamine, dimethylamine, methylethylamine, or diethylamine; hydrazine or hydrazine derivatives like N, N-dimethylhydrazine; solvents like water, alkanes, or tetrachlorocarbon; phosphor compounds like phosphor chloride, phosphane, trimethylphosphor, hexamethylphosphor triamide (HMTP) or trime- thylphosphonate; alcohols including monoalcohols like isopropanol or n-butanol and diols like ethylenediol, propylenediol, butane-1,4-diol, hexane-1 ,6-diol; thiols, in particular thiols further containing a hydroxyl group like 4-mercap- tophenol or 4-mercapotbenzylic alcohol; or boron compound like borane. The choice depends on the chemical structure of the desired inorganic compound. For oxides, it is preferable to use oxidants, plasma or water, in particular oxygen, water, oxygen plasma or ozone. For nitrides, it is preferably to use ammonia, hydrazine, hydrazine derivatives, nitrogen plasma or ammonia plasma. For borides, it is preferable to use boron compounds. For carbides, it is preferable to use alkanes or tetrachlorocarbon. For carbide nitrides, it is preferable to use mixtures including alkanes, tetrachlorocarbon, ammonia and / or hydrazine. Preferably, the decomposition compound has a vapor pressure of at least 1 mbar at 80 °C.

[0029] TEA and the decomposition compound are in the gaseous state when brought in contact with the organic particles. They can be brought into the gaseous state for example by heating them to elevated temperatures. In any case a temperature below the decomposition temperature of TEA or the decomposition compound has to be chosen. The decomposition temperature is the temperature at which the pristine TEA or the decomposition compound begins changing its chemical structure and composition. Preferably, the heating temperature ranges from 0 °C to 300 °C, more preferably from 10 °C to 200 °C, even more preferably from 15 °C to 150 °C, in particular from 20 °C to 100 °C.

[0030] Another way of bringing TEA or the decomposition compound into the gaseous state is direct liquid injection (DLI) as described for example in US 2009 10 226 612 A1. In this method TEA or the decomposition compound is typically dissolved in a solvent and sprayed in a carrier gas or vacuum. If the vapor pressure and the temperature of TEA or the decomposition compound are sufficiently high and the pressure is sufficiently low TEA or the decomposition compound is brought into the gaseous state. Various solvents can be used provided that TEA or the decomposition compound shows sufficient solubility in that solvent such as at least 1 g / l, preferably at least 10 g / l, more preferably at least 100 g / l. Examples for these solvents are coordinating solvents such as tetrahydrofuran, dioxane, diethoxyethane, pyridine or non-coordinating solvents such as hexane, heptane, benzene, toluene, or xylene. Solvent mixtures are also suitable. Alternatively, TEA or the decomposition compound can be brought into the gaseous state by direct liquid evaporation (DLE) as described for example by J. Yang et al. (Journal of Materials Chemistry C, volume 3 (2015), pages 12098- 12106). In this method, TEA is mixed with a solvent, for example a hydrocarbon such as tetradecane, and heated below the boiling point of the solvent. By evaporation of the solvent, TEA or the decomposition compound is brought into the gaseous state. This method has the advantage that no particulate contaminants are formed.

[0031] It is preferred to bring TEA or the decomposition compound into the gaseous state at decreased pressure. In this way, the process can usually be performed at lower heating temperatures leading to decreased decomposition of TEA. It is also possible to use increased pressure to push TEA or the decomposition compound in the gaseous state towards the solid substrate. Preferably, a pressure around ambient pressure, such as 0.8 to 1.2 bar, is used. Often, an inert gas, such as nitrogen or argon, is used as carrier gas for this purpose. Preferably, the partial pressure of TEA or the decomposition compound is 100 to 103mbar, more preferably 10 mbar to 0.01 mbar, in particular 5 to 0.05 mbar, such as 1 to 0.1 mbar.

[0032] TEA and the decomposition compound used in the process according to the present invention are used at high purity to achieve the best results. High purity means that the substance used contains at least 90 wt.-% TEA and the decomposition compound, preferably at least 95 wt.-%, more preferably at least 98 wt.-%, in particular at least 99 wt- %. The purity can be determined by elemental analysis according to DIN 51721 (Prufung fester Brennstoffe - Bestim- mung des Gehaltes an Kohlenstoff und Wasserstoff - Verfahren nach Radmacher-Hoverath, August 2001).

[0033] Contacting the organic particles with TEA and the decomposition compound in step (b) may be performed at a first temperature. The first temperature refers to the temperature of the organic particles while they are brought in contact with TEA and the decomposition compound in step (b). The temperature or the organic particles is typically controlled by adjusting the temperature of the gas and the apparatus surrounding the organic particles. The first temperature can be 20 °C to 100 °C, preferably 40 °C to 90 °C, in particular 50 °C to 80 °C.

[0034] The process may further comprises (c) sequentially contacting the organic particles with a TEA and a decomposition compound at a second temperature. As for step (b) a sequence can be performed which contains contacting the organic particles with a TEA and contacting the organic particles with a decomposition compound. This sequence can be performed 1 to 500 times, preferably 2 to 100 times, for example 3 to 20 times or 10 to 50 times. The sequence of step (c) can be performed fewer times than the sequence of step (b) or equal times or more often. Preferably, the sequence of step (c) is performed more times than the sequence of step (b), for example the sequence of step (c) is performed at least 1 .5 times the sequence of step (b) or the sequence of step (c) is performed at least two times the sequence of step (b). Preferably, residual TEA in the gaseous state is removed before the organic particles are brought in contact to the decomposition compound. Preferably, residual decomposition compound in the gaseous state is removed before the organic particles are brought in contact to TEA. Removal can be achieved by evacuation or by purging with an inert gas, for example nitrogen or argon. Hence, the sequence may contain contacting the organic particles with a TEA, removing residual TEA from the gas phase, contacting the organic particles with a decomposition compound and removing residual decomposition compound from the gas phase. Evacuation or purging can take 10 s to 1 h, preferably 1 to 45 min, in particular 5 to 30 min.

[0035] The second temperature refers to the temperature of the organic particles while they are brought in contact to TEA and the decomposition compound in step (c). The temperature or the organic particles is typically controlled by adjusting the temperature of the gas and the apparatus surrounding the organic particles. The second temperature can be 40 °C to 200 °C, preferably 60 °C to 150 °C, in particular 80 °C to 120 °C.

[0036] The second temperature may be at least 20 °C above the first temperature, preferably at least 25 °C, in particular at least 30 °C, for example at least 35 °C or at least 40 °C. It has been surprisingly found that such temperature difference makes the process suitable even for organic particles containing a sensitive compound and leads to a very low degree of agglomeration.

[0037] The method of the present invention may comprise the steps in the following order:

[0038] (a) bringing particles containing a halogen-containing organic compound in motion to each other,

[0039] (b) sequentially contacting the organic particles with TEA and a first decomposition compound in the gaseous state at a first temperature, and

[0040] (c) sequentially contacting the fluidized organic particles with TEA and a second decomposition compound in the gaseous state at a second temperature, wherein the second temperature is at least 20 °C above the first temperature.

[0041] The first decomposition compound may be less reactive with the first TEA than the second decomposition compound with the second TEA while the first TEA and the second TEA are the same. For example, the first decomposition compound may be isopropanol and the second decomposition compound may be water.

[0042] The first decomposition compound may be less reactive with TEA than the second decomposition compound with TEA, and the first decomposition compound is different to the second decomposition compound. For example, the first decomposition compound may be water, and the second decomposition compound may be ozone.

[0043] The present invention also relates to organic particles which can be obtained be the process according to the present invention. Unless explicitly stated to the contrary below, any description related to the process including preferred embodiments applies to the organic particles. The organic particles contain a core and a shell surrounding the core. The core contains an organic compound as described above for the process. Preferably, the core has a weight-mean average particle size of 0.5 to 1000 pirn, more preferably 1 to 200 m, even more preferably 2 to 100 pm, in particular 3 to 50 pm, for example 5 to 20 pm. Average particle size is preferably measured by light scattering.

[0044] The shell contains aluminum. Preferably, the shell contains at least 15 wt.-% aluminum, more preferably at least 20 wt.-% aluminum, in particular at least 25 wt.-% aluminum. Preferably, the shell contains aluminum oxide or an hydrated form of aluminum oxide, for example represented by the formula AIOx(OH)y, wherein 0 < x < 1.5; 0 < y < 3 and 2 x + y = 3, preferably 1 < x < 1 .5; 0 < y < 1 and 2 x + y = 3. Preferably, the shell contains at least 90 wt-% inorganic compound, even more preferably at least 95 wt.-%, in particular at least 98 wt.-%.

[0045] Preferably, the shell is conformal to the core. Preferably, the shell has a thickness of 0.5 to 100 nm, more preferably 1 to 50 nm, in particular 2 to 20 nm. The inner part of the shell may be thinner, of equal thickness or thicker than the outer shell. The inner shell may have a thickness of 0.2 to 100 nm, preferably 0.5 to 50 nm, in particular 1 to 15 nm. The outer shell may have a thickness of 0.2 to 100 nm, preferably 0.5 to 50 nm, in particular 1 to 15 nm.

[0046] The organic particles contain an interlayer between the core and the shell. The interlayer contains at least 5 atomic % aluminum and at least 5 atomic % of the halogen-containing organic compound. The interlayer has a thickness of less than the thickness of the shell, preferably less than 50 % of the thickness of the shell, in particular a thickness of less than 30 % of the shell, for example 0.1 to 20 % of the thickness of the shell. The interlayer thickness may have a thickness of 0.1 to 5 nm, preferably 0.2 to 2 nm, such as 0.3 to 1 nm.

[0047] The present invention further relates to a composition containing organic particles according to the present invention. The composition may be a composition for the use as agrochemical, in particular if the particles contain an insecticide, a herbicide or a fungicide. In this case, the composition is preferably a customary formulation type of agrochemical compositions, such as aqueous liquid capsule formulations (e.g. CS, ZC), pastes, pastilles, wettable powders or dusts (e.g. WP, SP, WS, DP, DS), pressings (e.g. BR, TB, DT), granules (e.g. WG, SG, GR, FG, GG, MG), insecticidal articles (e.g. LN), as well as gel formulations, e.g. for the treatment of plant propagation materials, such as seeds (e.g. GF). These and further composition types are defined in the "Catalogue of pesticide formulation types and international coding system”, Technical Monograph No. 2, 6thEd. May 2008, CropLife International.

[0048] The compositions are prepared in a known manner, such as described by Mollet and Grubemann, Formulation technology, Wiley VCH, Weinheim, 2001; or Knowles, New developments in crop protection product formulation, Agrow Reports DS243, T&F Informa, London, 2005.

[0049] Preferably, the composition contains one or more auxiliaries selected from solvents, liquid carriers, solid carriers or fillers, surfactants, dispersants, emulsifiers, wetters, adjuvants, solubilizers, penetration enhancers, protective colloids, adhesion agents, thickeners, humectants, repellents, attractants, feeding stimulants, compatibilizers, bactericides, anti-freezing agents, anti-foaming agents, colorants, tackifiers and binders.

[0050] Suitable solvents and liquid carriers are water and organic solvents, such as mineral oil fractions of medium to high boiling point, e.g. kerosene, diesel oil; oils of vegetable or animal origin; aliphatic, cyclic and aromatic hydrocarbons, e. g. toluene, paraffin, tetrahydronaphthalene, alkylated naphthalenes; alcohols, e.g. ethanol, propanol, butanol, benzyl alcohol, cyclohexanol; glycols; DMSO; ketones, e.g. cyclohexanone; esters, e.g. lactates, carbonates, fatty acid esters, gamma-butyrolactone; fatty acids; phosphonates; amines; amides, e.g. N-methylpyrrolidone, fatty acid dimethylamides; and mixtures thereof.

[0051] Suitable solid carriers or fillers are mineral earths, e.g. silicates, silica gels, talc, kaolins, limestone, lime, chalk, clays, dolomite, diatomaceous earth, bentonite, calcium sulfate, magnesium sulfate, magnesium oxide; polysaccharide powders, e.g. cellulose, starch; fertilizers, e.g. ammonium sulfate, ammonium phosphate, ammonium nitrate, ureas; products of vegetable origin, e.g. cereal meal, tree bark meal, wood meal, nutshell meal, and mixtures thereof.

[0052] Suitable surfactants are surface-active compounds, such as anionic, cationic, non-ionic and amphoteric surfactants, block polymers, polyelectrolytes, and mixtures thereof. Such surfactants can be used as emulsifier, dispersant, solubilizer, wetter, penetration enhancer, protective colloid, or adjuvant. Examples of surfactants are listed in McCutcheon's, Vol.1 : Emulsifiers & Detergents, McCutcheon's Directories, Glen Rock, USA, 2008 (International Ed. or North American Ed.).

[0053] Suitable anionic surfactants are alkali, alkaline earth or ammonium salts of sulfonates, sulphates, phosphates, carboxylates, and mixtures thereof. Examples of sulfonates are alkylarylsulfonates, diphenyl sulfonates, alpha-olefin sulfonates, lignin sulfonates, sulfonates of fatty acids and oils, sulfonates of ethoxylated alkyl phenols, sulfonates of alkoxy lated aryl phenols, sulfonates of condensed naphthalenes, sulfonates of dodecyl- and tridecylbenzenes, sulfonates of naphthalenes and alkylnaphthalenes, sulfosuccinates or sulfosuccinamates. Examples of sulphates are sulphates of fatty acids and oils, of ethoxylated alkylphenols, of alcohols, of ethoxylated alcohols, or of fatty acid esters. Examples of phosphates are phosphate esters. Examples of carboxylates are alkyl carboxylates, and carbox- ylated alcohol or alkyl phenol ethoxylate.

[0054] Suitable non-ionic surfactants are alkoxy lates, N-substituted fatty acid amides, amine oxides, esters, sugar-based surfactants, polymeric surfactants, and mixtures thereof. Examples of alkoxylates are compounds such as alcohols, alkyl phenols, amines, amides, aryl phenols, fatty acids or fatty acid esters which have been alkoxy lated with 1 to 50 equivalents. Ethylene oxide and / or propylene oxide may be employed for the alkoxy lation, preferably ethylene oxide. Examples of N-substituted fatty acid amides are fatty acid glucamides or fatty acid alkanolamides. Examples of esters are fatty acid esters, glycerol esters or monoglycerides. Examples of sugar-based surfactants are sorbitans, ethoxylated sorbitans, sucrose and glucose esters or alkylpolyglucosides. Examples of polymeric surfactants are home- or copolymers of vinylpyrrolidone, vinyl alcohols, or vinyl acetate.

[0055] Suitable cationic surfactants are quaternary surfactants, for example quaternary ammonium compounds with one or two hydrophobic groups, or salts of long-chain primary amines. Suitable amphoteric surfactants are alkylbetains and imidazolines. Suitable block polymers are block polymers of the A-B or A-B-A type comprising blocks of polyethylene oxide and polypropylene oxide, or of the A-B-C type comprising alkanol, polyethylene oxide and polypropylene oxide. Suitable polyelectrolytes are polyacids or polybases. Examples of polyacids are alkali salts of polyacrylic acid or polyacid comb polymers. Examples of polybases are polyvinylamines or polyethyleneamines.

[0056] Suitable adjuvants are compounds, which have a neglectable or even no pesticidal activity themselves, and which improve the biological performance of the compound I on the target. Examples are surfactants, mineral or vegetable oils, and other auxiliaries. Further examples are listed by Knowles, Adjuvants and additives, Agrow Reports DS256, T&F Informa UK, 2006, chapter 5.

[0057] Suitable thickeners are polysaccharides (e.g. xanthan gum, carboxymethylcellulose), inorganic clays (organically modified or unmodified), polycarboxylates, and silicates. Suitable bactericides are bronopol and isothiazolinone derivatives such as alkylisothiazolinones and benzisothiazolinones. Suitable anti-freezing agents are ethylene glycol, propylene glycol, urea and glycerin. Suitable anti-foaming agents are silicones, long chain alcohols, and salts of fatty acids. Suitable colorants (e.g. in red, blue, or green) are pigments of low water solubility and water-soluble dyes. Examples are inorganic colorants (e.g. iron oxide, titan oxide, iron hexacyanoferrate) and organic colorants (e.g. alizarin-, azo- and phthalocyanine colorants). Suitable tackifiers or binders are polyvinyl pyrrolidones, polyvinyl acetates, polyvinyl alcohols, polyacrylates, biological or synthetic waxes, and cellulose ethers.

[0058] The composition may be a composition for the use as cleaning composition, in particular if the particles contain a cleaning additive. In this case, preferably, the composition contains one or more of surfactants, bleaching agent, bleach catalysts, bleach activators, corrosion inhibitors, builders, enzymes, zinc salt.

[0059] Surfactants can be selected from anionic surfactants, amphoteric surfactants or non-ionic surfactants, preferably non-ionic surfactants, anionic surfactants are alkali metal and ammonium salts of Cs-Cis-alky I sulfates, of Cs-Cis-fatty alcohol polyether sulfates, of sulfuric acid half-esters of ethoxylated C4-Ci2-alky Iphenols (ethoxylation: 1 to 50 mol of ethylene oxide / mol), C12-C18 sulfo fatty acid alkyl esters, for example of C12-C18 sulfo fatty acid methyl esters, furthermore of Ci2-Ci8-alky Isulfonic acids and of Cio-Cis-alky lary Isulfonic acids, the sodium or potassium salts of stearic acid, oleic acid, palmitic acid, ether carboxylates, and alkylether phosphates. Amphoteric surfactants are those that bear a positive and a negative charge in the same molecule under use conditions. Preferred examples of amphoteric surfactants are so-called betaine-surfactants. Many examples of betaine-surfactants bear one quaternized nitrogen atom and one carboxylic acid group per molecule. A particularly preferred example of amphoteric surfactants is cocamidopropyl betaine (lauramidopropyl betaine). Non-ionic surfactants can be alkoxylated alcohols, di- and multiblock copolymers of ethylene oxide and propylene oxide and reaction products of sorbitan with ethylene oxide or propylene oxide, alkyl polyglycosides (APG), hydroxyalkyl mixed ethers and amine oxides.

[0060] Bleaching agents may be selected from chlorine bleach and peroxide bleach, and peroxide bleach may be selected from inorganic peroxide bleach and organic peroxide bleach. Preferred are inorganic peroxide bleaches, selected from alkali metal percarbonate, alkali metal perborate and alkali metal persulfate. Examples of organic bleaching agents are percarboxylic acids. The composition may contain 3 to 10 wt.-% of a bleaching agent.

[0061] Bleach catalysts can be selected from bleach-boosting transition metal salts or transition metal complexes such as, for example, manganese-, iron-, cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and copper complexes with nitrogen-containing tripod ligands and also cobalt-, iron-, copper- and ruthenium-amine complexes can also be used as bleach catalysts.

[0062] Bleach activators may be selected from N-methylmorpholinium-acetonitrile salts ("MMA salts”), trimethylammonium acetonitrile salts, N-acylimides such as, for example, N-nonanoylsuccinimide, 1,5-diacetyl-2,2 dioxohexahydro-1 , 3,5- triazine ("DADHT”) or nitrile quats (trimethylammonium acetonitrile salts), tetraacetylethylenediamine (TAED) and tetraacetylhexylenediamine.

[0063] Corrosion inhibitors are typcially compounds which inhibit the corrosion of metal. Examples of suitable corrosion inhibitors are triazoles, in particular benzotriazoles, bisbenzotriazoles, aminotriazoles, alkylaminotriazoles, also phenol derivatives such as, for example, hydroquinone, pyrocatechol, hydroxyhydroquinone, gallic acid, phloroglucinol or pyrogallol. Preferably, the composition comprises 0.1 to 1.5 wt.-% corrosion inhibitor.

[0064] Builders may be selected from organic and inorganic builders. Examples of suitable inorganic builders are sodium sulfate or sodium carbonate or silicates, in particular sodium disilicate and sodium metasilicate, zeolites, sheet silicates, in particular those of the formula o-Na2Si2O5, p-Na2Si2O5, and 6-Na2Si2O5, also fatty acid sulfonates, o-hydrox- ypropionic acid, alkali metal malonates, fatty acid sulfonates, alkyl and alkenyl disuccinates, tartaric acid diacetate, tartaric acid monoacetate, oxidized starch, and polymeric builders, for example polycarboxylates and polyaspartic acid. Examples of organic builders are especially polymers and copolymers. In one embodiment of the present invention, organic builders are selected from polycarboxylates, for example alkali metal salts of (meth)acrylic acid homopolymers or (meth)acrylic acid copolymers. Preferably, the composition contains 10 to 70 wt.-% builder.

[0065] Enzymes may be selected from lipases, hydrolases, amylases, proteases, cellulases, esterases, pectinases, lactases and peroxidases. Preferably, the composition contains 0.1 to 5 wt.-% enzyme. Zinc salts can be selected from water-soluble and water-insoluble zinc salts. Water-insoluble is used to refer to those zinc salts which, in distilled water at 25°C, have a solubility of 0.1 g / l or less. Zinc salts which have a higher solubility in water are accordingly referred to within the context of the present invention as water-soluble zinc salts. Preferably, the zinc salt is selected from zinc benzoate, zinc gluconate, zinc lactate, zinc formate, ZnCh, ZnSC>4, zinc acetate, zinc citrate, Zn(NOs)2, Zn(CH3SO3)2 and zinc gallate, preferably ZnCh, ZnSC , zinc acetate, zinc citrate, Zn(NOs)2, Zn(CH3SC>3)2 and zinc gallate, ZnO, ZnOaq, Zn(OH)2 and ZnCOs.

[0066] Examples

[0067] Example 1 (comparative)

[0068] A fluidized bed reactor was charged with 10 g of saflufenacil powder having an average particle size of 50 m. Before reaction the powder was dried in an inert gas atmosphere at 50 °C for 12 hours under fluidization and vibration. Afterwards the powder was fluidized, heated to a temperature of 50 °C and exposed to trimethyl aluminum (TMA) vapor for 40 min. The delivery of TMA was realized by opening a needle valve to 5 % by an overall reactor pressure of 10 mbar. In addition, 40 seem N2 were used as a carrier gas into the reactor chamber. Saturation would take more than 1 .5 hours in this case. After said time, the TMA vapor was removed by purging with nitrogen. Subsequently, water vapor was brought in contact to the powder in the same manner as above for eight minutes. After purging, nine cycles consisting of 4 min TMA and 45 s water exposure are performed.

[0069] The thus obtained particles were subject to a scanning electron microscopy analysis. A sample is prepared by freezing in liquid ethylene and fractured. An image of a broken particle is depicted in Figure 1a, wherein the lower left part shows the core of the particle. EDX mapping was done to detect aluminum in the same image, which is shown in Figure 1b. EDX mapping for sulfur introduced by saflufenacil is shown in Figure 1c. One can see that aluminum is diffused into the particle, so a mixed layer of aluminum and saflufenacil is formed indicating a potential loss of saflufenacil due to reaction with TMA within the particle.

[0070] Example 2

[0071] To study the penetration of TMA into saflufenacil thin films were prepared which resemble the surface on the particles.

[0072] Example 2a (comparative)

[0073] A saflufenacil film was spin coated onto a silicon wafer coupon of size about 1 cm x 1 cm. A solution containing 50 mg / mL saflufenacil in methyl ethyl ketone (MEK) solvent was used, and the film thickness is about 120-130 nm. The spin rate is 4000 rpm for 60 s. ALD depositions were done on a GemStar 6 reactor (Arradiance Inc.). The reactor was equipped with dual manifold lines which can be heated up to 200°C to prevent undesired film coatings on the manifold walls. On the manifold lines, there were 8 ALD ports connected with high-speed ALD valve to control the precursor dosage. Nitrogen was used as the carrier gas and the flow was controlled by a mass flow controller. TMA was used as ALD precursor and water as decomposition compound. Both reagent supplies were kept at room temperature. As for the ALD condition, the pulse time for TMA were 30 ms, and 150 ms, respectively. The spin coated saflufenacil film was kept at 50°C during ALD coating. The pulse time of water was 30 ms. 15 s purge time for both TMA and water was used.

[0074] Example 2b (inventive): Example 2a was repeated with triethyl aluminum (TEA) instead of TMA. The supply for TEA was kept at 50 °C.

[0075] Example 2c (comparative): Example 2a was repeated, wherein the film was kept at a temperature of 50 °C during ALD deposition.

[0076] Example 2d (inventive): Example 2c was repeated with triethyl aluminum (TEA) instead of TMA. The supply for TEA was kept at 50 °C.

[0077] Depth profile of the samples of example 2a and 2b were done by X-ray photoemission spectroscopy (XPS) measurement on PHI VersaProbe III and PHI VersaProbe IV. The sample were sputtered with Ar ions with 1 kV and 0.7 piA. Figure 2a shows the result for the TMA film (example 2a) and figure 2b shows the result for the TEA film (example 2b). The Al signal in Figure 2a slowly decays with the depths until the silicon substrate is reached, while the Al signal in Figure 2b sharply decreases to about zero well before the silicon substrate is reached. Hence, TMA significantly penetrates the saflufenacil film while TEA stays almost entirely on the surface of the saflufenacil film.

[0078] The samples of examples 2c and 2d were subjected to angle resolved XPS. The results are depicted in Figure 3. It can be seen that TEA tends to stronger Al-F and AI-CI interactions than TMA. Without intending to be bound by any theory, it is believed that TEA reacts stronger with halogens on the surface hindering the penetration into the film and thus retaining more active ingredient unaffected.

Claims

Claims1 . A process for preparing coated organic particles comprising: a. bringing organic particles containing a halogen-containing organic compound in motion to each other, wherein the halogen-containing organic compound consists of nonmetals, b. sequentially contacting the organic particles with triethyl aluminum and a decomposition compound in the gaseous state.

2. The process according to claim 1, wherein in step (b) the temperature of the organic particles is 40 °C to 90 °C.

3. The process according to claim 1 or 2, wherein the organic particles are fluidized.

4. The process according to any of the claims 1 to 3, wherein the decomposition compound is water.

5. The process according to any of the claims 1 to 4, wherein step (b) comprises a sequence containing contacting the organic particles with a metal- or semimetal-containing compound, removing residual metal- or semi- metal-containing compound from the gas phase, contacting the organic particles with a decomposition compound and removing residual decomposition compound from the gas phase.

6. The process according to any of the claims 1 to 5, wherein contacting the organic particles with triethyl aluminum and a decomposition compound is performed 2 to 100 times.

7. The process according to any of the claims 1 to 6, wherein the organic particles the organic particles are brought in contact with a pretreatment compound in the gaseous state before step (b), wherein the pretreatment compound is water, an alcohol or a carboxylic acid.

8. The process according to any of the claims 1 to 7, wherein in step (b) the organic particles are at a first temperature and the process further comprises a (c) sequentially contacting the organic particles with a triethyl aluminum and a decomposition compound at a second temperature, wherein the second temperature is at least 20 °C above the first temperature.

9. Organic particles containing: a. a core containing a halogen-containing organic compound, wherein the core is essentially free of aluminum and wherein the halogen-containing organic compound consists of nonmetals, b. a shell containing aluminum, wherein the shell is essentially free of the halogen-containing organic compound, andc. an interlayer between the core and the shell containing at least 5 atomic % aluminum and at least 5 atomic % of the halogen-containing organic compound, wherein the interlayer has a thickness of less than the thickness of the shell.

10. The organic particles according to claim 9, wherein the core has a weight-mean average particle size of 0.5 to 100 pm.11 . The organic particles according to claim 9 or 10, wherein shell has a thickness of 0.5 to 100 nm, more preferably 1 to 50 nm.

12. The organic particles according to any of the claims 9 to 11, wherein the shell contains aluminum oxide.

13. A composition containing the organic particles according to any of the claims 9 to 12.

14. The composition according to claim 13, wherein the particles contain an insecticide, fungicide, or herbicide and one or more auxiliaries selected from solvents, liquid carriers, solid carriers or fillers, surfactants, dispersants, emulsifiers, wetters, adjuvants, solubilizers, penetration enhancers, protective colloids, adhesion agents, thickeners, humectants, repellents, attractants, feeding stimulants, compatibilizers, bactericides, antifreezing agents, anti-foaming agents, colorants, tackifiers and binders.

15. The composition according to claim 13, wherein the particles contain a cleaning additive and one or more of surfactants, bleaching agent, bleach catalysts, bleach activators, corrosion inhibitors, builders, and enzymes.

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